I had a Dual Mono BII setup with consumer SPDIF and two Legato 3.1 in balanced mode for a couple of months without issue, however, I just recently hooked up the Volumite to be able to bypass my preamp.

Hookup is as per Integration guide with DVCC supplied by one of the DAC DVCC and regulator bypassed. No jumper changed from previous setup and controller on both boards removed.

The sound is working and volume can be adjusted without any issue but playing a few pieces that I have listened to many times in the past sounds a lot different... Like if the sound was monoral instead of stereo... Also, one of the phase was inverted and I had to switch my speaker terminal polarity...

One piece in Miles Davis Kind of Blue (Flamenco Sketches), the trumpet plays on the right side and then later on switches to the left side. Now when it is supposed to play on the left side, the trumpet stays centered but plays like if it was from a distance much further back in the stage and with some echo...

Any idea what it could be or what I forgot to change?

I have installed the Volumite so I can modify my preamp but right now it sounds like ...

Thanks
Do

Hey glt!

You always amaze me man!

I don't know how I missed this one but you surely caught it!

All working beautifully now and sounding amazing!! I just wish I could motorize the volumite pot!

Thanks
Do

I used to program alot many years ago but lost interest in it...

Maybe its time to get back into it!

Ciao!
Do

This is mentioned in the Advanced Features chapter of the BII guide. The table gives you the output specification for both the left and the right boards.

Yes, but the same applies to the - also of course. And the right mono channel is a mirror of the left.

Yes I saw the docs but I'm puzzled...

What I was wondering was should I use the + on each side or the - on each side of the same board

In stereo mode you have left + gnd - and the same on the right channel but in dual mono I do understand it is the opposite side of the board that carries the inverse phase, it's just to know if I take the + of both sides or the - . or + on the phase and - on the anti-phase.

Please see picture
BII IV out

Thanks
Do

No, flipping the phase was not done for those who don't want to think about phase, It was done because it makes practical sense if you want to get the best DNR possible. :) That is something people should definitely think about!

Sure it might seem daunting at first, until you are capable of thinking it through. :)

It actually not very confusing you just need to understand what and why. :)

In dual mono mode Both DACs output precisely the same signal just with one side phase flipped(Which is exactly how the Wolfson and TI chips do dual mono BTW, so its not a new concept) , if you want you can sum the current of the two sides by joining left + to right - and right + to left -.

Edited by user Friday, September 2, 2011 9:13:13 PM(UTC)  | Reason: Not specified

Ok so lets start with some definitions:

OSR = output stage for balanced right output
OSL = output stage for balanced left output

Choose which input on each output stage you want to be +(normal phase) and which will be -(inverted phase). They are marked on each output stage board as "dac input left" and "dac input right", for this example I will assume you use "dac input left" for in+ and "dac input right" for in- on each board. From now on I will refer to those an "in+" and "in-" respectively.

For the left channel configured Buf 2 you will wire DAC outputs to output stage inputs like this:
Left + and Right - (both joined in parallel)to OSL in+
Left - and Right + (both joined in parallel)to OSL in-

For the right channel configured Buf 2 you will wire like this
Right + and Left - (both joined in parallel)to OSR in+
Right - and Left + (both joined in parallel)to OSR in-

Of course you should connect GND to each output stage input GND as well.

Your situation is different from IVY-III and Legato 3.1 (and the apps for TI and Wolfson) because the signals are not run through a differential amp (which helps with DNR by canceling common mode signals).

I truly hope that helps. If you still have questions its ok, ask away.

Edited by user Saturday, September 3, 2011 6:53:29 AM(UTC)  | Reason: Not specified